dart2js: Measure time of individual optimization passes.

pkg/compiler/lib/src/apiimpl.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library leg_apiimpl;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:package_config/packages.dart';
@@ skipping 437 matching lines @@
     return setupPackages(uri).then((_) {
       assert(packages != null);
 
       return super.run(uri).then((bool success) {
         int cumulated = 0;
         for (final task in tasks) {
           int elapsed = task.timing;
           if (elapsed != 0) {
             cumulated += elapsed;
             log('${task.name} took ${elapsed}msec');
+            for (String subtask in task.subtasks) {
+              int subtime = task.getSubtaskTime(subtask);
+              log('${task.name} > $subtask took ${subtime}msec');
+            }
           }
         }
         int total = totalCompileTime.elapsedMilliseconds;
         log('Total compile-time ${total}msec;'
             ' unaccounted ${total - cumulated}msec');
         return success;
       });
     });
   }
 
@@ skipping 58 matching lines @@
     print('$message: ${tryToString(exception)}');
     print(tryToString(stackTrace));
   }
 
   fromEnvironment(String name) => environment[name];
 
   LibraryInfo lookupLibraryInfo(String libraryName) {
     return library_info.LIBRARIES[libraryName];
   }
 }